A relatively new display system has been developed which generates images in all three physical dimensions. The system relies on the generation within a confined space, typically, a closed dome, of a volume upon which coherent light impacts to create the images. Each image is comprised of a number of light pixels (called voxels) usually generated by one or more laser beams impacting on the generated volume within the dome.
The defined volume can be created by spinning a helix shaped surface (disk) within the dome so that as the disk spins a volume is created defined by the disk surface as it moves up and down in a helical curve. Thus, at any point in time a different height of the volume is at a given physical location within the dome. A light spot can then be created by impacting a beam of coherent light with the disk at a particular point in time coinciding with the height desired for that point of light. By timing a large number of such light beams, three dimensional objects can be created within the dome and these objects then can be viewed from any position since the spinning disk (which creates the display volume) is essentially transparent to the eye. Such a system is the subject of U.S. patent application Ser. No. 07/409,176.
One critical aspect of such a system is the very fast processing and generation of the light points which are distributed in space and time and which must be very precisely timed and spatially positioned if the resulting image is to be free of jitter. Thus, it is necessary to generate signals representative of the light points that are desired on a continuing basis and then to direct the laser light beams to those points at precisely the right physical location and at the precisely the right time.
A further requirement of such a system is that different light colors are required and these must all be positioned to impact at the same precise point.
One goal of such a system is to generate images from known x,y,z data and then once the images are generated, to actually display them in the created volume. This presents several optical challenges in the design of the system. Some of these problems include the coverage of the entire volume, the trade-off between resolution and speed, and how many points to display and with what resolution. Some of these trade-offs stem from how quickly a signal can be switched from one point to another within the volume versus how small the point can be focused.
The optical problem begins with the fact that the scanner has a very limited output divergent angle and thus, it is important to amplify that divergence to fill up the display volume optically. However, when that angle is diverged, the width of the laser beam is also diverged. The divergence reduces the resolution of the beam. In order to achieve a 3-dimensional image, beams may be intercepted by the helical screen at any depth in the volume. This requires the beams to maintain a small diameter throughout the path length inside the volume display in contrast to typical laser printers or projectors where a small focus is achieved only in a single plane.
A set of signals must be generated to drive the acousto-optics at the proper time. The image that is produced is critically dependent on that timing and on the spatial positioning of the modulated coherent light beam.
Thus, there exists in the art a need for an optic system that works at extremely high speeds and that can both spatially and temporally control the positioning of coherent light beams.
A further need exists in the art for such a system and method which allows for different colors of light and which allows for each light color to be positioned in exactly the same physical space.
A still further need exists in the art for such a system which allows for easy adjustment for different created volumes and which can handle different disk shapes.